Hi Nellaroo

I also am proud owner of a new HYHY. I am on tank 1, and average mileage since purchase is 27.5 mpg in (hilly) Seattle suburban commuting. Of course this means sometimes it is downhill..not just uphill. Most of my trips are at least 30 minutes long in stop and start heavy highway traffic. I have noticed that on short trips I do have lower mileage. Worst was when my husband drove 30 miles all uphill to mountains to ski. Then it got 20 mpg. The downhill ride homme cancelled this out, by his report at 30 mpg. I have not altered my car in anyway from delivery (no change in tire pressure,etc).

To confirm your observation: I have also noticed the shuddery feeling at about 55-60 miles per hour on highway - I think it is when electric cuts in and out. It is a little bit annoying but not terrible. I am hoping that it will not bug me too much over time.Anyone else?

PS - it is time for my first fill up. Can I really use regular gas?